#include <iostream>

using namespace std;

int main()
{
    int a1,a2,a3,a4;
    cin>>a1;
    cin>>a2;
    cin>>a3;
    cin>>a4;
    if (a1==a2 && a1==a3)
        cout <<"eto chetvertoe chislo .\n";
    if (a2==a3 && a2==a4)
        cout <<"eto pervoe chislo .\n";
    if (a3==a1&& a3==a4)
        cout <<"eto vtoroe chislo .\n";
    if (a4==a2&&a4==a1)
        cout <<"eto trete chislo .\n";
    return 0;
}


